While uncovering my boat this spring I discovered one of my aluminum risers appeared to be cracked. Starting the boat the other day I confirmed it when a small spit of water continued to flow while running. I must have been in a hurry when winterizing and didn't top off the port side manifold completely leaving raw water in there. At least it wasn't the motor. Lesson learned. Now I've gotta replace them and I'm trying to decide if it's worth it to buy the SS riser or go with what I already have the aluminum. Are the any gains other than they look better? Right now I've got a hard time justifying spending more than twice the money on something that I don't really need. It on a 7.4mpi so I can't imagine I'm gonna gain anything. What do ya think?

You won't gain anything on a stock 7.4. However, I would be sure that there is no further damage anywhere else. You could have just as easily left a pocket of water elsewhere.
Eddie

Your scaring me now. I did run it for awhile on the hose and all looked good no milky oil, smoke or noises. The true test would be at higher RPM out on the water but I'm hesitant to take it out with a cracked exhaust. I know it's not gonna explode or anything but I still don't wanna be on the water if it fails somehow. How would you check other than looking at the oil and listening to the motor?

You can pressure test the entire cooling system. Use a tee to couple the hoses from the thermostat housing. On the other leg of the tee, install a pressure gauge. You can then rig up an air hose to put in the sea pump outlet water hose. Put a ball valve on the air line so that you can control exactly how much air you put in the cooling system. Put about 20 psi to it and let it sit. If it holds, you are good to go. Don't go over 25 psi or you run the risk of lifting the stock head gaskets.
Eddie